|
  |	smovecr.sa 3.1 12/10/90
  |
  |	The entry point sMOVECR returns the constant at the
  |	offset given in the instruction field.
  |
  |	Input: An offset in the instruction word.
  |
  |	Output:	The constant rounded to the user's rounding
  |		mode unchecked for overflow.
  |
  |	Modified: fp0.
  |
  |
  |		Copyright (C) Motorola, Inc. 1990
  |			All Rights Reserved
  |

  |       For details on the license for this file, please see the
  |       file, README, in this same directory.

  
  |SMOVECR	idnt	2,1 | Motorola 040 Floating Point Software Package
  
  	|section 8
  
  #include "fpsp.h"
  
  	|xref	nrm_set
  	|xref	round
  	|xref	PIRN
  	|xref	PIRZRM
  	|xref	PIRP
  	|xref	SMALRN
  	|xref	SMALRZRM
  	|xref	SMALRP
  	|xref	BIGRN
  	|xref	BIGRZRM
  	|xref	BIGRP
  
  FZERO:	.long	00000000
  |
  |	FMOVECR
  |
  	.global	smovcr
  smovcr:
  	bfextu	CMDREG1B(%a6){#9:#7},%d0 |get offset
  	bfextu	USER_FPCR(%a6){#26:#2},%d1 |get rmode
  |
  | check range of offset
  |
  	tstb	%d0		|if zero, offset is to pi
  	beqs	PI_TBL		|it is pi
  	cmpib	#0x0a,%d0		|check range $01 - $0a
  	bles	Z_VAL		|if in this range, return zero
  	cmpib	#0x0e,%d0		|check range $0b - $0e
  	bles	SM_TBL		|valid constants in this range
  	cmpib	#0x2f,%d0		|check range $10 - $2f
  	bles	Z_VAL		|if in this range, return zero
  	cmpib	#0x3f,%d0		|check range $30 - $3f
  	ble	BG_TBL		|valid constants in this range
  Z_VAL:
  	fmoves	FZERO,%fp0
  	rts
  PI_TBL:
  	tstb	%d1		|offset is zero, check for rmode
  	beqs	PI_RN		|if zero, rn mode
  	cmpib	#0x3,%d1		|check for rp
  	beqs	PI_RP		|if 3, rp mode
  PI_RZRM:
  	leal	PIRZRM,%a0	|rmode is rz or rm, load PIRZRM in a0
  	bra	set_finx
  PI_RN:
  	leal	PIRN,%a0		|rmode is rn, load PIRN in a0
  	bra	set_finx
  PI_RP:
  	leal	PIRP,%a0		|rmode is rp, load PIRP in a0
  	bra	set_finx
  SM_TBL:
  	subil	#0xb,%d0		|make offset in 0 - 4 range
  	tstb	%d1		|check for rmode
  	beqs	SM_RN		|if zero, rn mode
  	cmpib	#0x3,%d1		|check for rp
  	beqs	SM_RP		|if 3, rp mode
  SM_RZRM:
  	leal	SMALRZRM,%a0	|rmode is rz or rm, load SMRZRM in a0
  	cmpib	#0x2,%d0		|check if result is inex
  	ble	set_finx	|if 0 - 2, it is inexact
  	bra	no_finx		|if 3, it is exact
  SM_RN:
  	leal	SMALRN,%a0	|rmode is rn, load SMRN in a0
  	cmpib	#0x2,%d0		|check if result is inex
  	ble	set_finx	|if 0 - 2, it is inexact
  	bra	no_finx		|if 3, it is exact
  SM_RP:
  	leal	SMALRP,%a0	|rmode is rp, load SMRP in a0
  	cmpib	#0x2,%d0		|check if result is inex
  	ble	set_finx	|if 0 - 2, it is inexact
  	bra	no_finx		|if 3, it is exact
  BG_TBL:
  	subil	#0x30,%d0		|make offset in 0 - f range
  	tstb	%d1		|check for rmode
  	beqs	BG_RN		|if zero, rn mode
  	cmpib	#0x3,%d1		|check for rp
  	beqs	BG_RP		|if 3, rp mode
  BG_RZRM:
  	leal	BIGRZRM,%a0	|rmode is rz or rm, load BGRZRM in a0
  	cmpib	#0x1,%d0		|check if result is inex
  	ble	set_finx	|if 0 - 1, it is inexact
  	cmpib	#0x7,%d0		|second check
  	ble	no_finx		|if 0 - 7, it is exact
  	bra	set_finx	|if 8 - f, it is inexact
  BG_RN:
  	leal	BIGRN,%a0	|rmode is rn, load BGRN in a0
  	cmpib	#0x1,%d0		|check if result is inex
  	ble	set_finx	|if 0 - 1, it is inexact
  	cmpib	#0x7,%d0		|second check
  	ble	no_finx		|if 0 - 7, it is exact
  	bra	set_finx	|if 8 - f, it is inexact
  BG_RP:
  	leal	BIGRP,%a0	|rmode is rp, load SMRP in a0
  	cmpib	#0x1,%d0		|check if result is inex
  	ble	set_finx	|if 0 - 1, it is inexact
  	cmpib	#0x7,%d0		|second check
  	ble	no_finx		|if 0 - 7, it is exact
  |	bra	set_finx	;if 8 - f, it is inexact
  set_finx:
  	orl	#inx2a_mask,USER_FPSR(%a6) |set inex2/ainex
  no_finx:
  	mulul	#12,%d0			|use offset to point into tables
  	movel	%d1,L_SCR1(%a6)		|load mode for round call
  	bfextu	USER_FPCR(%a6){#24:#2},%d1	|get precision
  	tstl	%d1			|check if extended precision
  |
  | Precision is extended
  |
  	bnes	not_ext			|if extended, do not call round
  	fmovemx (%a0,%d0),%fp0-%fp0		|return result in fp0
  	rts
  |
  | Precision is single or double
  |
  not_ext:
  	swap	%d1			|rnd prec in upper word of d1
  	addl	L_SCR1(%a6),%d1		|merge rmode in low word of d1
  	movel	(%a0,%d0),FP_SCR1(%a6)	|load first word to temp storage
  	movel	4(%a0,%d0),FP_SCR1+4(%a6)	|load second word
  	movel	8(%a0,%d0),FP_SCR1+8(%a6)	|load third word
  	clrl	%d0			|clear g,r,s
  	lea	FP_SCR1(%a6),%a0
  	btstb	#sign_bit,LOCAL_EX(%a0)
  	sne	LOCAL_SGN(%a0)		|convert to internal ext. format
  
  	bsr	round			|go round the mantissa
  
  	bfclr	LOCAL_SGN(%a0){#0:#8}	|convert back to IEEE ext format
  	beqs	fin_fcr
  	bsetb	#sign_bit,LOCAL_EX(%a0)
  fin_fcr:
  	fmovemx (%a0),%fp0-%fp0
  	rts
  
  	|end